fix: disable serial no scanning for picklist

Current design of picklist doc doesn't have "picked serial no" so it
doesn't make much sense to scan it. Instead it should increment qty
only. Might add this in future after fixing UX problems
diff --git a/erpnext/stock/doctype/pick_list/pick_list.js b/erpnext/stock/doctype/pick_list/pick_list.js
index 82663e3..799406c 100644
--- a/erpnext/stock/doctype/pick_list/pick_list.js
+++ b/erpnext/stock/doctype/pick_list/pick_list.js
@@ -166,7 +166,8 @@
 			qty_field: 'picked_qty',
 			max_qty_field: 'qty',
 			dont_allow_new_row: true,
-			prompt_qty: frm.doc.prompt_qty
+			prompt_qty: frm.doc.prompt_qty,
+			serial_no_field: "not_supported",  // doesn't make sense for picklist without a separate field.
 		};
 		const barcode_scanner = new erpnext.utils.BarcodeScanner(opts);
 		barcode_scanner.process_scan();